# Proposed AD FAA-2010-0548: Bombardier, Inc. Model BD-700-1A10 and BD-700-1A11 Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2010-23-08
- Products: Bombardier
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: June 4, 2010, 75 FR 31731
- Comments due: July 19, 2010
- Became: [AD 2010-23-08](https://openairdocs.org/ad/2010-23-08)
- Docket: FAA-2010-0548 (https://www.regulations.gov/docket/FAA-2010-0548, where comments are filed)
- Project: 2010-NM-041-AD
- FR document: 2010-13419
- Official PDF: https://openairdocs.org/files/sha256/16/8f/168f46f92dbec41ba609ed07ef0a8fd214026aebe22c31a384834e75c9bffca1 (from https://www.govinfo.gov/content/pkg/FR-2010-06-04/pdf/2010-13419.pdf)
- Federal Register: https://www.federalregister.gov/documents/2010/06/04/2010-13419/airworthiness-directives-bombardier-inc-model-bd-700-1a10-and-bd-700-1a11-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/8441774F0D69D07686257738004EFBE3.0001
- Page: https://openairdocs.org/proposed/FAA-2010-0548

## Summary

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Following five reported cases of balance washer screw failure on similar RATs [ram air turbines]/air driven generators installed on other aircraft types, an investigation * * * determined that a specific batch of the screws had a metallographic non-conformity that increased their susceptibility to brittle fracture. * * * Failure of a balance washer screw can result in loss of the related balance washer, with consequent turbine imbalance. Such imbalance could potentially result in RAT structural failure (including blade failure), loss of RAT electrical power and structural damage to the aircraft and, if deployment was activated by a dual engine shutdown, could also result in loss of hydraulic power for the flight controls [and consequent reduced ability of the flightcrew to maintain the safe flight and landing of the airplane]. * * * * *

The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

## Notices in this docket

- Jun 4, 2010: Notice of proposed rulemaking (NPRM). (first notice), FR document 2010-13419, comments due Jul 19, 2010 (https://www.federalregister.gov/documents/2010/06/04/2010-13419/airworthiness-directives-bombardier-inc-model-bd-700-1a10-and-bd-700-1a11-airplanes)

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